Improvement in valves for steam-engines



return motion.

UNITED STATES EaTEET GETCE.

i ALEXANDER K. RIDER, (-)F NAZARETH, PENNSYLVANIA, ASSIGNOR TO HIMSELIX C. H. DELAMATER, AND G. H. REYNOLDS.

IMPROVEMENT IN VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 793,483@ dated June 2, 1868.

in the State ot' Pennsylvania, have inventedcertain new and useful Improvements in the Valve-Gear for Steam-Engines; and I do hereby declare that the following is a full and exact description thereof.

My invention is intended more particularly for steam pumping-engines, steam-hammers, and the like varietiesaof engines, in which no cranks or equivalent working parts are employed. It provides for operating the valves with great rapidity and certainty, with simple mechanism, and without the necessity for any mechanical connection.

I will first describe what I consider the best means of carrying out my invention, and will afterward designate the points which I believe to be` new therein.

The accompanying drawings `form a part of this specication.

Figure 1 is a central longitudinal section. Fig. 2 is a cross-section on the line S S of Fig. l. Fig. 3 is a cross-section on the line T T of Fig. 1. Fig. 4 is a longitudinal section on the crooked line U Uin Fig. 2. In this figure the piston has just arrived at the left extreme of its motion, and the valve has just been thrown to the right, so as to induce a Fig. 5 is a corresponding section of a portion, showing the parts in the position which they assume when the piston has arrived at the opposite end of the stroke. The valve has in this figure just been thrown to the left.

Similar letters of reference indicate like parts in all the figures.

A is the main body of the cylinder, and B is the piston; There are the ordinary cylinder-ports a a and the ordinary exhaustport a. In addition to these cavities there are two small chambers, C1 C2, connected with the 'exhaust-passage, and provided with ports which `I term master-valves D1 D2; These valves are provided with internal passages d1 d, and the chambers O1 C2 are connected by small passages with the interior of the main cylinder, and with the interior of the steam chest or main-valve chamber E, as will be described below.

Gr is the slide-valve of a semi-cylindrical form. is equivalent in function to the ordinary cupvalve. g g are stout necks connecting this valve with pistons G1 G2. I prefer to form the valve and pistons with their necks in a single piece, but it is not essential. The entire lower side of the valve-chamber is finished by boring, so as to form a true cylindrical surface,- and the chamber is cylindrical throughout, except for a small space in the middle, as represented. The pistons G' G2 are adapted to till th-e chamber, so as to work nearly or quite steam-tight. The lower face of the valve G is turned, and is finished by scraping or otherwise, to form a steam-tight contact with the semi-cylindrical lower side of the valve-chamber. This mode of finishing the surfaces of these rubbing parts allows a tighttit to be produced with very little expense.

H is a shaft, which may be provided with a stuffing-box. (Not represented.) It aidsin starting the engine by means of the arm h, which works in a corresponding cavity in the back of the main valve G. The hollow throat in the bottom of the valve performs the same function relatively to the ports on the semicylindrical surface as the hollow throat of the ordinary dat slide-valve performs relatively to the ports of ordinary engines.

Each ot' the master-valves D1 Dz has three diameters at different points, as represented. Thelargest part forms a steam-tight or nearly steam-tight contact with the interior of the chamber. The next smaller diameter is sufficiently smaller `to afford an annular area for the action of the steam to move itself, and also-to form a passage for the admission of steam to move the main valve. The smallest diameter forms a steam-tight or nearly steamtight t in the cylindrical passage which leads to the exhaust. The position which the master-valves maintain during the greater portion ot' the time is at the extremeinner end ot' their traverse. In this position the shoulder where the smaller part changes to the intermediate size serves as a puppet-valve, and increases the tightness with which the passage to the exhaust-port is stopped.

In Fig. 1 the piston is moving to the right, the strong steam from the valve-chamber entering freely on the left side of the piston, and

It has a cavity on its under face, and

the exhaust escaping freely from the right side of the piston. The necks g-g are so much smaller than the pistons G1 G2 that the steam flows readily through the cavity thus provided.

The provision for operating the main valve throughV the medium `of the master-valves is worthy of special description. There is one passage from each master-valve chamber into the main-valve chamber, andthere are two passages from each master-valve chamber into the interior of the main cylinder. Contining our attention for the present to the right end of the cylinder, :o designates theepassage between the main-valve chamber and the mastervalve chamber, while y and a designate, re-

- spectvely, the twopassages `between .the master-valve chamber and `the interior of the-cylinder, the passage e being ciose to the end of the cylinder, and the passagey being situated a little more than the thickness of the Vmain right it covers the passage g/ without-produc-v ing any ei'ect; but when, by theclose :ap-

proach of the main piston B to the end of its stroke, it uncovers the passage y,and exposes it to the livesteam, (the position indicated in outline v in Fig. 1,) the strong steam :flows up through the passage y, llsthe annular chamber around the master -valve D2, .and throws this little valve tothe right. .This movement uncovers the passage w, and exposes it to the live steam, which, owing through it, acts against the outer end of the valve-piston G2, and throws itand itsattachments very rapidly to the left. This latter movement, as will vbe readily understood, entirely reverses the action of the steam upon the main piston-B, admitting the` strong steam from the valve-chamber to the rightside. of this piston, and exhausting the steam from the left side. This exhaust action also allows strong steam, which had just gone up through the passages yand a', to flow back again. The strong steam, filling the mainy cylinder on the right side of the piston, flowsup through the passage z, and, acting against the end ofthe sub-valve D2, moves it to the left, thusrestoring it to its original position, (that represented in thev drawing,) and the main piston-B commences to move to the left under the `ordinary conditions which obtain in steam-engineering-that is to say, the full pressureFof the steam is exerted on the right side of the piston, and the left side is free to exhaust intothe atmosphere, or into acondenser, it'such be' employed.

The same construction and the same arrangement obtain at the left end of the cylinder. As the main piston B approaches either end of the cylinder the master-valve at that end (which is previously in equilibrium) vis thrown actively by the admission ,of steam der `has a bore ot' lfour, inches.

into the annular space, and on movingiituncovers the port or passagev @admits steam against the end ofthe valve-piston,and throws the main valve, immediately after which the master-valve returns to its original position at the' inner extreme of its motion. By the change in the' conditions in which the-steam isiadmittedito themaincylinder the passage through the interior of the master-valve by the latter movement becomes available to discharge the steam from the end of the valvepiston, so that the main valve and its pistons are in equilibrium, both ends being open to the-exhaust for nearly the whole period. It is only subjected to the action of steam on either end alternately for a very short space of time at the moment when-thechange takes place.

The proportions and forms of the parts may -vary'within wide limits. I-have represented the master-valves and their` chambers as mounted a little one side ofthe-center,l or of the line between the axis vof the main-valve chamber and the axis-ot' the'main cylinder. l have represented thezma'in ports as being in their ordinary central position. It' maybe preferable,- to` some lmeasons,-to.arrange the main ports a little one side of their vcentral position, so as to accommodate the mastervalvesand their chambers and passagespby placing them more nearly in thecentral A:position. Many such rchanges in position :and many changes in the form and weight'of `'the parts maybe made withoutmaterially impairing the useful effect of my invention. I prefer, however, to make the master-valves-very small-considerably smaller -in ordinarypractice than are here represented. The small- .ness of the weight of these actively-moving parts avoids-any injurious jerkor concussion .only one-fourth-ot' an inch in diameterrand the holesthroughthe master-valveare only one-sixteenth'of yan inch in diameter. -Icon- Sider it important .to-cushion the steam in the endsof the main-valve chamber, to bring the main valve and lits pistons-to rest gradually. I effect this-by contracting the-passage for the escapeofthe steam from the master-valve.

i1, #are bushings screwed `into the passages d1, d2 for the purposeaofl stillfurther contracting the area of the passage. In .myexperii mentalengiIxe I have .thus contracted' the passage to one-twentieth of an inch in diameter. The precise area of this passage, as also the magnitude of all the important ports, may be modified as experience shall determine. I nd that the dimensions above given serve very well with my small engine. I found, upon contracting the-diameter of the passage by bushings il i2 to much less than one-twen tieth of an inch, the main valve would not throw to its full and proper extent, while an enlargement of the hole much beyond onetwentieth of an inch, orthe omission of the bushing altogether, allowed the main valve and its connected pistons to strike against the ends of their chambers.

I propose to introduce a block of wood, or spiral or other spring, or a mass of lead or soft metal, either in the ends of the chambers or in the corresponding faces ofthe piston, or in each, in order to deaden the concussion when such occurs from any cause. I nd a liability to concussion in starting when the ports are cold, and consider the provision just referred to mainly valuable in such contingencies.

The outer end of the shaft H is square, to allow the application of a wrench or handle, by means of which the main valve can be thrown from one end to the other by hand in warming the engine preparatory to starting. I prefer to apply a permanent handle on the end of this shaft, and to make the cavity in which the end of the arm h works of such length that the valve can be thrown its full extent in one direction or the other without turning the shaft H.

I can, by modifications of the construction and arrangement, and by varying the proportions of my ports and passages, so work the water-valves, and also the main valve, that they shall stand under the pressure of the live steam at the end during the most part of the time, and be kept by a brief period in exhaustion. This will be the opposite, in this respect, of the conditions above described, wherein these ports stand most of the time under the pressure only ofthe exhaust-steam, and are exposed only for very brief periods to the pressure of the strong steam.

I prefer the arrangement which IA have represented; but either may be used Without departing from the principle of my invention.

My invention is substantially involved in any modification ,of these parts where the motion not only of the main valve, but also of the master-valves, is accomplished by the action of the steam itself, without intermediate mechanism.

Some of the advantages due to certain features of my invention may be separately enumerated as follows:

First, by reason of the fact that my mastervalves D1 D2 are furnished with the passages y and z, I am able to throw the master-valve, and thus ultimately the main valve, by the action ofthe steam itself, without any mechanical connection, and to effect this with rapidity and certainty greater, I believe, than is obtained with complicated and expensive constructions.

Second, by reason of the fact that my passages to the master-valve are contracted to such a caliber as will allow the exhaust-steam to escape from the ends of the main-valve chamber with only a limited speed, I am able, while insuring acomplete emptying of the said chain ber at each end, to so modify the current which escapes before the piston when .the valve is suddenly thrown by the steam as to effectually cushion and soften the concussion without preventing the valve from making its full throw, and to do this without in any wise affecting the velocity with which the live steam is admitted to act on the valve-piston,because the live steam Hows through other and independent passages, which may be as much larger as shall be found desirable.

Third, by reason of the fact that my cupvalve Gr has a cylindrical surface, and is reciprocated back and forward longitudinally of the cylindrical seat in which it bears, I am able, while using a form of the surface which can be produced with mathematical exactness by the ordinary machine tools for boring and turning, to secure a fit which will remain perfect for a long period, and which will allow the valve to be driven by the action of steam or other force directly applied to the ends without a necessity for intermediate mechanism.

Having now fully described my invention, what I claim as new therein, and desire to secure by Letters Patent, is as follows:

The master-valves Dl D2, operated by, and controlling, in turn, the action of the steam in throwing the main valve Gr, substantially as and for the purposes herein set forth.

In testimony whereof I have hereunto set my name in presence of two subscribing witnesses.

.ALEXR K. RIDER.

Witnesses:

W. C. DEY, C. U; LivINes. 

